System and method for the manufacture of surgical blades

ABSTRACT

A method for manufacturing surgical blades from either a crystalline or poly-crystalline material, preferably in the form of a wafer, is disclosed. The method includes preparing the crystalline or poly-crystalline wafers by mounting them and machining trenches into the wafers. The methods for machining the trenches, which form the bevel blade surfaces, include a diamond blade saw, laser system, ultrasonic machine, and a hot forge press. The wafers are then placed in an etchant solution which isotropically etches the wafers in a uniform manner, such that layers of crystalline or poly-crystalline material are removed uniformly, producing single or double bevel blades. Nearly any angle can be machined into the wafer which remains after etching. The resulting radii of the blade edges is 5-500 nm, which is the same caliber as a diamond edged blade, but manufactured at a fraction of the cost.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.10/383,573 filed Mar. 10, 2003, now U.S. Pat. No. 7,105,103. Relatedsubject matter is disclosed in two U.S. provisional patent applications,Ser. No. 60/362,999, filed Mar. 11, 2002, and Ser. No. 60/430,332, filedDec. 3, 2002, the entire contents of which are expressly incorporatedherein by reference.

FIELD OF THE INVENTION

The invention relates to a system and method for the manufacture ofsurgical instruments. More particularly, the invention relates to asystem and method for the manufacture of surgical-quality bladesmanufactured from silicon and other crystalline materials.

BACKGROUND OF THE INVENTION

Existing surgical blades are manufactured via several differentmethodologies, each method having its own peculiar advantages anddisadvantages. The most common method of manufacture is to mechanicallygrind stainless steel. The blade is subsequently honed (through avariety of different methods such as ultrasonic slurrying, mechanicalabrasion and lapping) or is electrochemically polished to achieve asharp edge. The advantage of these methods is that they are proven,economical processes to make disposable blades in high volume. Thegreatest disadvantage of these processes is that the edge quality isvariable, in that achieving superior sharpness consistency is still achallenge. This is primarily due to the inherent limitations of theprocess itself. Blade edge radii can range from 30 nm to 1000 nm.

A relatively new method of blade manufacture employs coining of thestainless steel in lieu of grinding. The blade is subsequentlyelectrochemically polished to achieve a sharp edge. This process hasbeen found to be more economical than the grinding method. It has alsobeen found to produce blades with better sharpness consistency. Thedisadvantage of this method is that the sharpness consistency is stillless than that achieved by the diamond blade manufacturing process. Theuse of metal blades in soft tissue surgery is prevalent today due totheir disposable cost and their improved quality.

Diamond blades are the gold standard in sharpness in many surgicalmarkets, especially in the ophthalmic surgery market. Diamond blades areknown to be able to cleanly cut soft tissue with minimal tissueresistance. The use of diamond blades is also desired due to theirconsistent sharpness, cut after cut. Most high-volume surgeons will usediamond blades since the ultimate sharpness and sharpness variability ofmetal blades is inferior to that of diamond. The manufacturing processused to make diamond blades employs a lapping process to achieve anexquisitely sharp and consistent edge radius. The resultant blade edgeradii range from 5 nm to 30 nm. The disadvantage of this process is thatit is slow and as a direct result, the cost to manufacture such diamondblades ranges from $500 to $5000. Therefore, these blades are sold forreuse applications. This process is currently used on other, less hardmaterials, such as rubies and sapphires, to achieve the same sharpnessat a lesser cost. However, while less expensive than diamonds, rubyand/or sapphire surgical quality blades still suffer from thedisadvantage that the cost of manufacture is relatively high, rangingfrom $50 to $500, and their edges only last through about two hundredcases. Therefore, these blades are sold for reuse and limited reuseapplications.

There have been a few proposals for the manufacture of surgical bladesusing silicon. However, in one form or another, these processes arelimited in their ability to manufacture blades in various configurationsand at a disposable cost. Many of the silicon blade patents are based onanisotropic etching of silicon. The anisotropic etching process is onewhere the etching is highly directional, with different etch rates indifferent directions. This process can produce a sharp cutting edge.However, due to the nature of the process, it is limited by the bladeshapes and included bevel angles that can be attained. Wet bulkanisotropic etching processes, such as those employing potassiumhydroxide (KOH), ethylene-diamine/pyrcatechol (EDP) andtrimethyl-2-hydroxethylammonium hydroxide (TMAH) baths, etch along aparticular crystalline plane to achieve a sharp edge. This plane,typically the (111) plane in silicon <100>, is angled 54.7° from thesurface plane in the silicon wafers. This creates a blade with anincluded bevel angle of 54.7°, which has been found to be clinicallyunacceptable in most surgical applications as too obtuse. Thisapplication is even worse when this technique is applied to makingdouble bevel blades, for the included bevel angle is 109.4°. The processis further limited to the blade profiles that it can produce. The etchplanes are arranged 90° to each other in the wafer. Therefore, onlyblades with rectangular profiles can be produced.

Thus, a need exists to manufacture blades that address the shortcomingsof the methods discussed above. This system and method of the presentinvention can make blades with the sharpness of diamond blades at thedisposable cost of the stainless steel methods. In addition, the systemand method of the present invention can produce blades in high volumeand with tight process control.

SUMMARY OF THE INVENTION

The above described disadvantages are overcome and a number ofadvantages are realized by the present invention which relates to asystem and method for the manufacturing of surgical blades from acrystalline or poly-crystalline material, such as silicon, whichprovides for the machining of trenches in a crystalline orpoly-crystalline wafer, by various means, at any desired bevel angle orblade configuration. The machined crystalline or poly-crystalline wafersare then immersed in an isotropic etching solution which uniformlyremoves layer after layer of molecules of the wafer material, in orderto form a cutting edge of uniform radius, and of sufficient quality forsoft tissue surgery applications. The system and method of the inventionprovides a very inexpensive means for the manufacture of such highquality surgical blades.

It is therefore an object of the invention to provide a method formanufacturing a surgical blade, comprising the steps of mounting asilicon or other crystalline or poly-crystalline wafer on a mountingassembly, machining one or more trenches on a first side of thecrystalline or poly-crystalline wafer, etching the first side of thecrystalline or poly-crystalline wafer to form one or more surgicalblades, singulating the surgical blades, and assembling the surgicalblades.

It is a further object of the invention to provide a method formanufacturing a surgical blade, comprising the steps of mounting acrystalline or poly-crystalline wafer on a mounting assembly, machiningone or more trenches on a first side of the crystalline orpoly-crystalline wafer, coating the first side of the crystalline orpoly-crystalline wafer with a coating, dismounting the crystalline orpoly-crystalline wafer from the mounting assembly, and remounting thefirst side of the crystalline or poly-crystalline wafer on the mountingassembly, machining a second side of the crystalline or poly-crystallinewafer, etching the second side of the crystalline or poly-crystallinewafer to form one or more surgical blades, singulating the surgicalblades, and assembling the surgical blades.

It is still a further object of the invention to provide a method formanufacturing a surgical blade, comprising the steps of mounting acrystalline or poly-crystalline wafer on a mounting assembly, machiningone or more trenches on a first side of the crystalline orpoly-crystalline wafer, dismounting the crystalline or poly-crystallinewafer from the mounting assembly, and remounting the first side of thecrystalline or poly-crystalline wafer on the mounting assembly,machining a second side of the crystalline or poly-crystalline wafer,etching the second side of the crystalline or poly-crystalline wafer toform one or more surgical blades, converting a layer of the crystallineor poly-crystalline material to form a hardened surface, singulating thesurgical blades, and assembling the surgical blades.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features and advantages of the present invention will best beunderstood by reference to the detailed description of the preferredembodiments which follows, when read in conjunction with theaccompanying drawings, in which:

FIG. 1 illustrates a flow diagram of a method for manufacturing a doublebevel surgical blade from silicon according to a first embodiment of thepresent invention;

FIG. 2 illustrates a flow diagram of a method for manufacturing a singlebevel surgical blade from silicon according to a second embodiment ofthe present invention;

FIG. 3 illustrates a flow diagram of an alternative method formanufacturing a single bevel surgical blade from silicon according to athird embodiment of the present invention;

FIG. 4 illustrates a silicon wafer mounted on a mounting assembly, topview;

FIG. 5 illustrates a silicon wafer mounted on a mounting assembly withtape, side view;

FIG. 6 illustrates the use of a laser waterjet for pre-cutting a siliconwafer to assist in the machining of trenches in the silicon waferaccording to an embodiment of the present invention;

FIGS. 7A-7D illustrate dicing saw blade configurations used to machinetrenches in a silicon wafer according to an embodiment of the presentinvention;

FIG. 8 illustrates the operation of a dicing saw blade through a siliconwafer mounted on support backing according to an embodiment of thepresent invention;

FIGS. 8A-8C illustrate a use of slots when machining trenches in asilicon wafer with a dicing saw blade according to an embodiment of theinvention;

FIG. 9 illustrates a cross-section view of a dicing saw blade machininga trench in a silicon wafer that is tape mounted according to anembodiment of the present invention;

FIGS. 10A and 10B illustrate a silicon surgical blade with a singlebevel cutting edge and a silicon surgical blade with a double bevelcutting edge respectively, made in accordance with an embodiment of thepresent invention;

FIG. 11 illustrates a block diagram of a laser system used to machinetrenches in a silicon wafer according to an embodiment of the presentinvention;

FIG. 12 illustrates a block diagram of an ultrasonic machining systemused to machine trenches in a silicon wafer according to an embodimentof the present invention;

FIG. 13 illustrates a diagram of a hot-forging system used to formtrenches in a silicon wafer according to an embodiment of the presentinvention;

FIG. 14 illustrates a silicon wafer with a single machined trench with acoating applied to the machined side according to an embodiment of thepresent invention;

FIG. 15 illustrates a cross-section view of a dicing saw blade machininga second trench in a silicon wafer that is tape mounted according to anembodiment of the present invention;

FIG. 16 illustrates a cross-section image of a silicon wafer that hasbeen machined trenched on both sides according to an embodiment of thepresent invention;

FIGS. 17A and 17B illustrate an isotropic etching process performed on asilicon wafer with machined trenches on both sides according to anembodiment of the present invention;

FIGS. 18A and 18B illustrate an isotropic etching process on a siliconwafer with machined trenches on both sides, and a coating layer on oneside according to an embodiment of the present invention;

FIG. 19 illustrates a resultant cutting edge of a double bevel siliconsurgical blade with a coating on one side manufactured according to anembodiment of the present invention;

FIGS. 20A-20G illustrate various examples of surgical blades that can bemanufactured in accordance with the method of the present invention;

FIGS. 21A and 21B illustrate a side view of the blade edge of a siliconsurgical blade manufactured in accordance with an embodiment of thepresent invention, and a stainless steel surgical blade, at 5,000×magnification, respectively;

FIGS. 22A and 22B illustrate a top view of the blade edge of a siliconsurgical blade manufactured in accordance with an embodiment of thepresent invention, and a stainless steel blade, at 10,000×magnification, respectively;

FIGS. 23A and 23B illustrate an isotropic etching process on a siliconwafer with a machined trench on one side, and a coating layer on anopposite side according to a further embodiment of the presentinvention;

FIG. 24 illustrates a post-slot assembly of a handle and a surgicalblade manufactured in accordance with an embodiment of the invention;and

FIGS. 25A and 25B illustrate profile perspectives of a blade edge madeof a crystalline material, and a blade edge made of a crystallinematerial that includes a layer conversion process in accordance with anembodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The various features of the preferred embodiments will now be describedwith reference to the drawing figures, in which like parts areidentified with the same reference characters. The following descriptionof the presently contemplated best mode of practicing the invention isnot to be taken in a limiting sense, but is provided merely for thepurpose of describing the general principles of the invention.

The system and method of the present invention provides for themanufacture of surgical blades to be used for incising soft tissue.Although the preferred embodiment is shown to be a surgical blade,numerous cutting devices can also be fabricated in accordance with themethods discussed in detail below. Therefore, it will be apparent to oneskilled in the art of the invention that although reference is made to“surgical blades” throughout these discussions, numerous other types ofcutting devices can be fabricated, including, for example, medicalrazors, lancets, hypodermic needles, sample collection cannula and othermedical sharps.

The preferred base material that the blades will be manufactured from iscrystalline silicon with a preferred crystal orientation. However, otherorientations of silicon are suitable, as well as other materials thatcan be isotropically etched. For example, silicon wafers withorientation <110> and <111> can also be used, as well as silicon wafersdoped at various resistivity and oxygen content levels. Also, wafersmade of other materials can be used, such as silicon nitride and galliumarsenide. Wafer form is the preferred format for the base material. Inaddition to crystalline materials, poly-crystalline materials can alsobe used to manufacture surgical blades. Examples of thesepoly-crystalline materials include polycrystalline silicon. It will beunderstood that the term “crystalline” as used herein will be used torefer to both crystalline and poly-crystalline materials.

Therefore, it will be apparent to one skilled in the art of theinvention that although reference is made to “silicon wafers” throughoutthese discussions, any of the aforementioned materials in combinationwith various orientations can be used in accordance with the variousembodiments of the present invention, as well as other suitablematerials and orientations that might become available.

FIG. 1 illustrates a flow diagram of a method for manufacturing a doublebevel surgical blade from silicon according to a first embodiment of thepresent invention. The method of FIGS. 1, 2 and 3 describe generallyprocesses which can be used to manufacture silicon surgical bladesaccording to the present invention. However, the order of the steps ofthe method illustrated in FIGS. 1, 2 and 3 can be varied to createsilicon surgical blades of different criteria, or to meet differentmanufacturing environments. As such, the method of FIGS. 1, 2 and 3 aremeant to be representative of general embodiments of the methodaccording to the present invention, in that there are many differentpermutations which include the same steps that can result in amanufactured silicon surgical blade in accordance with the spirit andscope of the present invention.

The method of FIG. 1 is used to manufacture a double bevel surgicalblade, preferably with a crystalline material such as silicon, inaccordance with an embodiment of the invention, and begins with step1002. In step 1002, the silicon wafer is mounted on mounting assembly204. In FIG. 4, the silicon wafer 202 is shown mounted on a waferframe/UV tape assembly (mounting assembly) 204. The mounting assembly204 is a common method to handle silicon wafer material in thesemiconductor industry. One skilled in the art can appreciate thatmounting the silicon (crystalline) wafer 202 upon a wafer mountingassembly 204 is not necessary for the manufacture of surgical bladesaccording to the preferred embodiments of the invention

FIG. 5 illustrates the same silicon wafer 202 mounted on the samemounting assembly 204 but in a side view (left or right; it issymmetrical, though that need not be the case). In FIG. 5, silicon wafer202 is mounted on tape 308 which is then mounted on mounting assembly204. Silicon wafer 202 has a first side 304 and a second side 306.

Referring again to FIG. 1, decision step 1004 follows step 1002.Decision step 1004 determines whether an optional pre-cut is to be madein silicon wafer 202, in step 1006, if so desired. This pre-cut can beperformed by a laser waterjet 402, as shown in FIG. 6. In FIG. 6, laserwaterjet 402 is shown directing laser beam 404 onto silicon wafer 202,which is mounted on mounting assembly 204. As can be seen in FIG. 6,various pre-cut holes (or through-hole fiducials) 406 can be created insilicon wafer 202 as a result of the impact of the laser beam 404 withsilicon wafer 202.

Silicon wafer 202 is ablated by the laser beam 404 upon silicon wafer202. The ability of the laser beam 404 to ablate the silicon wafer 202is related to the laser's wavelength λ. In the preferred embodiment,which uses a silicon wafer, the wavelength that yields the best resultsis 1064 nano-meters, typically provided by a YaG laser, though othertypes of lasers can be used as well. If a different crystalline orpoly-crystalline material is used, then other wavelengths and lasertypes will be more appropriate.

The resultant through-hole fiducials 406 (a plurality of holes can becut in this manner) can be used as guides for machining trenches(discussed in detail with respect to step 1008 below), especially if adicing saw blade is to be used to machine the trenches. Through-holefiducials 406 can also be cut by any laser beam (e.g., an excimer laseror laser waterjet 402) for the same purpose. The pre-cut through-holefiducials are typically cut in the shape of a plus “+” or a circle.However, the choice of through-hole fiducial shape is directed by thespecific manufacturing tools and environment, and thus need not belimited to just the two aforementioned shapes.

In addition to the use of a laser beam to pre-cut through-holefiducials, other mechanical machining methods can also be used. Theseinclude, for example, but are not limited to, drilling tools, mechanicalgrinding tools and an ultra-sonic machining tool 100. While use of thedevices is novel with respect to the preferred embodiments of theinvention, the devices and their general use are well known to thoseskilled in the art.

Precutting can be performed to silicon wafer 202 prior to machiningtrenches in order for silicon wafer 202 to maintain its integrity andnot fall apart during the etching process. A laser beam (e.g., a laserwaterjet 402 or excimer laser) can be used to scroll in ellipticalthrough-hole slots for the dicing blade 502 (discussed in detail inreference to FIGS. 7A-7C) to begin machining trenches in silicon wafer202 within its perimeter. The mechanical machining devices and methods(discussed above) used to create the through-hole fiducials can also beused to create the through-hole slots as well.

Referring again to FIG. 1, the next step is step 1008, which can followeither step 1006 (if through-hole fiducials 406 are cut into siliconwafer 202), or steps 1002 and 1004, which is the silicon wafer mountingstep (“step” 1004 is not a physical manufacturing step; these decisionsteps are included to illustrate the total manufacturing process and itsvariances). In step 1008, trenches are machined into first side 304 ofsilicon wafer 202. There are several methods that can be used to machinethe trenches, dependent on manufacturing conditions and the desireddesign of the finished silicon surgical blade product.

The methods for machining can employ either a dicing saw blade, lasersystem, an ultrasonic machining tool or a hot-forging process. Othermethods for machining can also be used. Each will be discussed in turn.The trench that is machined by any of these methods provides the angle(bevel angle) of the surgical blade. As the trench machine operates onsilicon wafer 202, silicon material is removed, either in the shape ofthe dicing saw blade, the pattern formed by the excimer laser, or thepattern formed by an ultrasonic machining tool, in the desired shape ofthe surgical blade preform. In the case of a dicing saw blade, thesilicon surgical blades will have only straight edges; in the latter twomethods, the blades can be essentially any shape desired. In the case ofa hot-forging process, the silicon wafer is heated to make it malleable,then pressed between two die, each one having a three dimensional formof the desired trenches to be “molded” into the heated, malleablesilicon wafer. For purposes of this discussion, “machining” trenchesencompasses all methods of manufacturing trenches in a silicon wafer,including those mentioned specifically, whether by a dicing saw blade,excimer laser, ultrasonic machine or a hot-forging process, andequivalent methods not mentioned. These methods of machining thetrenches will now be discussed in detail.

FIGS. 7A-7D illustrate dicing saw blade configurations used to machinetrenches in a silicon wafer according to an embodiment of the invention.In FIG. 7A, first dicing saw blade 502 exhibits angle Φ which willessentially be the resulting angle of the surgical blade after theentire manufacturing process has been completed. FIG. 7B illustratessecond dicing saw blade 504, with two angled cutting surfaces, eachexhibiting a cutting angle Φ. FIG. 7C illustrates third dicing saw blade506 which also has cutting angle Φ, but has a slightly differentconfiguration than that of first dicing saw blade 502. FIG. 7Dillustrates a fourth dicing saw blade 508 with two angled cuttingsurfaces, similar to FIG. 7B, each exhibiting a cutting angle Φ.

Although each of the dicing saw blades 502, 504, 506 and 508 illustratedin FIGS. 7A-7D have the same cutting angle Φ, it will be apparent to oneskilled in the art that the cutting angle can be different for differentuses of the silicon based surgical blades. In addition, as will bediscussed below, a single silicon surgical blade can have differentcutting edges with different angles included therein. Second dicing sawblade 504 can be used to increase the manufacturing capacity for aparticular design of a silicon based surgical blade, or, produce siliconsurgical blades that have two or three cutting edges. Various examplesof blade designs will be discussed in detail in reference to FIGS.20A-20G. In a preferred embodiment of the invention, the dicing sawblade will be a diamond grit saw blade.

A special dicing saw blade is used to machine channels in the first side304 of the silicon wafer 202. The dicing saw blade composition isspecifically chosen to provide the best resultant surface finish whilemaintaining acceptable wear life. The edge of the dicing saw blade isshaped with a profile that will shape the resultant channel in siliconwafer 202. This shape will correlate to the resultant blade bevelconfiguration. For instance, surgical blades typically have includedbevel angles that range from 15° to 45° for single bevel blades and halfincluded bevel angles that range from 15° to 45° for double bevelblades. Selection of a dicing saw blade in conjunction with etchconditions provides precise control of bevel angle.

FIG. 8 illustrates the operation of a dicing saw blade through a siliconwafer mounted on support backing according to an embodiment of theinvention. FIG. 8 illustrates the operation of a dicing saw blademachine that is machining trenches in first side 304 of silicon wafer202. In this example, any of the dicing saw blades of FIGS. 7A-7D (502,504, 506 or 508) can be used to create the silicon based surgical bladeedges. It should also be understood that the blade configurations ofFIGS. 7A-7D are not the only possible configurations that can be createdfor dicing saw blades. FIG. 9 illustrates a cross section view of adicing saw blade machining a trench in a silicon wafer that is tapemounted according to an embodiment of the invention. FIG. 9 illustratesa close up cross section view of the same dicing saw blade assemblyshown in FIG. 8 actually penetrating silicon wafer 202. It can be seenthat dicing saw blade 502 does not penetrate all the way through siliconwafer 202, but, for a single bevel cut, penetrates approximately 50-90%of the thickness of silicon wafer 202. This applies to any method usedfor machining (or molding, via hot-forging) a single bevel trench. For adouble bevel cut by any dicing saw blade, or, any of the machiningmethods, approximately 25-49% of the thickness of silicon wafer 202 willbe machined away (or molded) on each side of silicon wafer 202. FIGS.10A and 10B illustrate a silicon surgical blade with a single bevelcutting edge and a silicon surgical blade with a double bevel cuttingedge respectively, made in accordance with an embodiment of theinvention.

As discussed above, slots can also be cut into the silicon wafer 202,especially if a dicing saw blade will be used to machine the trenches.Slots can be cut into the silicon wafer 202 in a fashion similar to thethrough-hole fiducials, i.e., with the laser water-jet or excimer laser,but serve a very different purpose. Recall that the through-holefiducials are used by the trench machine in order to accurately positionthe silicon wafer 202 on the trench machine. This is especially usefulwhen making double bevel blades, because the second machining (on theopposite side of the silicon wafer 202) must be accurately positioned toensure a properly manufactured double bevel blade. Slots, however, areused for a different purpose. Slots allow the dicing saw blade to begincutting the silicon wafer 202 away from the edge (as shown in FIG. 8),without splintering or breaking the silicon wafer 202. This is thepreferred embodiment, as is shown in FIG. 8A. Referring to FIG. 8, it isapparent that if slots are not used, and the trenches are machined asshown, the machined silicon wafer 202 will be susceptible to breakagealong the machined trenches because the silicon wafer is significantlythinner in those areas, and small stresses can cause it to break. Thatis, the machined silicon wafer of FIG. 8 lacks structural rigidity.Compare this to the silicon wafer of FIG. 8C. The machined silicon wafer202 of FIG. 8C is much more rigid and leads to improved manufacturingthroughput. Fewer silicon wafers 202 machined according to FIG. 8C willbreak than those of FIG. 8. As shown in FIGS. 8A and 8B, the slot ismade wider than the dicing saw blade, and long enough to allow thedicing saw blade to be inserted into it to begin machining at the properdepth. Therefore, the dicing saw blade does not attempt to cut thesilicon wafer 202 while it is moving downward, which causes splinteringand breakage; the dicing saw blade begins to cut when it is moving in anhorizontal manner, as it was designed to do. FIG. 8C illustrates aseries of slots and machined trenches in a first side of a silicon wafer202.

FIG. 11 illustrates a block diagram of a laser system used to machinetrenches in a silicon wafer according to an embodiment of the invention.The trenches can also be ultrasonically machined as described inreference to FIG. 12, discussed in detail below. The advantage of thesetwo methods is that blades can be manufactured with non-linear andcomplex cutting edge profiles, e.g. crescent blades, spoon blades, andscleratome blades. FIG. 11 illustrates a simplified laser machineassembly 900. The laser machine assembly 900 is comprised of a laser902, which emits a laser beam 904, and a multi-axis control mechanism906 which rests on base 908. Of course, the laser machine assembly 900can also comprise a computer, and possibly a network interface, whichhave been omitted for clarity.

When machining trenches with the laser machine assembly 900, the siliconwafer 202 is mounted on the mounting assembly 204 which also isadaptable to be manipulated by multi-axis control mechanism 906. Throughthe use of laser machining assembly 900 and various light beam maskingtechniques, an array of blade profiles can be machined. The light beammask is located inside laser 902, and through careful design, preventslaser 902 from ablating silicon material where it is not intended. Fordouble bevel blades, the opposing side is machined the same way usingthe pre-cut chamfers 206A, 206B or fiducials 406 for alignment.

Laser 902 is used to accurately and precisely machine trench patterns(also referred to as an “ablation profile” in reference to use of alaser) into either first side 304 or second side 306 of silicon wafer202 in preparation of the wet isotropic etching step (which is discussedin detail with reference to FIG. 1, step 1018). Multi-axis control andthe use of internal laser light beam masks are used to raster theaforementioned ablation profiles in silicon wafer 202. As a result, acontoured trench is achieved that has shallow angled slopes thatcorrespond to that which is required for the surgical blade product.Various curvilinear profile patterns can be achieved via this process.There are several types of lasers that can be used in this machiningstep. For example, an excimer laser or laser waterjet 402 can be used.The wavelength of the excimer laser 902 can range between 157 nm and 248nm. Other examples include a YaG laser and lasers with a wavelength of355 nanometers. Of course, one skilled in the art can appreciate thatlaser beams with certain wavelengths within the range of 150 nm to11,000 nm can be used to machine trench patterns.

FIG. 12 illustrates a block diagram of an ultrasonic machining systemused to machine trenches in a silicon wafer according to an embodimentof the present invention. Ultrasonic machining is performed by using aprecisely machined ultrasonic tool 104 that is then used to machine,with abrasive slurry 102, first side 304 or second side 306 of siliconwafer 202. The machining is done to one side at a time. For double bevelblades, the opposing side is machined the same way using thethrough-hole fiducials 406 for alignment.

Ultrasonic machining is used to accurately and precisely machine trenchpatterns into the silicon wafer 202 surface in preparation for the wetisotropic etching step. Ultrasonic machining is performed byultrasonically vibrating a mandrel/tool (tool) 104. Tool 104 does notcome in contact with silicon wafer 202, but is in close proximity tosilicon wafer 202 and excites abrasive slurry 102 by operation ofultrasonic waves emitted by tool 104. The ultrasonic waves emitted bytool 104 force abrasive slurry 102 to erode silicon wafer 202 to thecorresponding pattern that is machined on tool 104.

Tool 104 is machined, via milling, grinding or electrostatic dischargemachining (EDM), to create the trench pattern. The resultant pattern onthe machined silicon wafer 202 corresponds to that which was machined ontool 104. The advantage of using an ultrasonic machining method over anexcimer laser is that an entire side of silicon wafer 202 can havenumerous blade trench patterns ultrasonically machined at the same time.Thus, the process is fast and relatively inexpensive. Also, like theexcimer laser machining process, various curvilinear profile patternscan be achieved via this process.

FIG. 13 illustrates a diagram of a hot-forging system used to formtrenches in a silicon wafer according to an embodiment of the invention.The trench configurations can also be hot forged into the wafer surface.This process employs heating the wafer to a malleable condition. Thewafer surfaces are subsequently pressed between two die that incorporatethe negative pattern to that of the resultant trenches.

Silicon wafer 202 is pre-heated in a heat chamber, or can be heatedcompletely by operation of heated base member 1054, upon which siliconwafer 202 sits. After sufficient time at elevated temperatures haspassed, silicon wafer 202 will become malleable. Then, heated die 1052is forced down upon silicon wafer 202 with sufficient pressure toimpress the negative image of heated die 1052 into first side 304 ofsilicon wafer 202. The design of die 1052 can be such that there arenumerous trenches of various bevel angles, depths, lengths and profiles,in order to create virtually any blade design imaginable. The diagramillustrated in FIG. 13 is greatly simplified and exaggerated to clearlyshow the pertinent features of the hot-forging process.

Having discussed the several methods for machining trenches, attentionis again redirected to FIG. 1. Following step 1008, in which thetrenches are machined into first side 304 of silicon wafer 202, adecision must be made, in decision step 2001, as to whether to coat thesilicon wafer 202. FIG. 14 illustrates a silicon wafer with a singlemachined trench with a coating applied to the machined side, accordingto an embodiment of the present invention. If a coating is to beapplied, then coating 1102 can be applied to first side 304 of siliconwafer 202 in step 2002 according to one of many techniques known tothose skilled in the art of the invention. Coating 1102 is supplied tofacilitate etching control and to provide additional strength to theresultant blade edge. Silicon wafer 202 is placed in a depositionchamber where the entire first side 304 of silicon wafer 202—includingthe flat area and the trenched area—is coated with a thin layer ofsilicon nitride (Si₃N₄). The resultant coating 1102 thickness can rangefrom 10 nm to 2 microns. The coating 1102 can be comprised of anymaterial that is harder than the silicon (crystalline) wafer 202.Specifically, coating 1102 can also be comprised of titanium nitride(TiN), aluminum titanium nitride (AlTiN), silicon dioxide (SiO₂),silicon carbide (SiC), titanium carbide (TiC), boron nitride (BN) ordiamond-like-crystals (DLC). Coatings for double bevel surgical bladeswill be discussed again in greater detail below, in reference to FIGS.18A and 18B.

After coating 1102 has been applied in optional step 2002, the next stepis step 2003, dismounting and remounting (step 2003 can also follow step1008 if no coating was applied). In step 2003, silicon wafer 202 isdismounted from tape 308 utilizing the same standard mounting machine.The machine dismounts silicon wafer 202 by radiating ultra-violet (UV)light onto the UV sensitive tape 308 to reduce its tackiness. Low tackor heat release tape can also be used in lieu of UV sensitive tape 308.After sufficient UV light exposure, silicon wafer 202 can be easilylifted from the tape mounting. Silicon wafer 202 is then remounted, withsecond side 306 facing up, in preparation for machine trenching ofsecond side 306.

Step 2004 is then performed on silicon wafer 202. In step 2004, trenchesare machined into second side 306 of silicon wafer 202, as was done instep 1008, in order to create double bevel silicon based surgicalblades. FIG. 15 illustrates a cross-section view of a dicing saw blade502 machining a second trench in silicon wafer 202 that is tape mounted,according to an embodiment of the invention. Of course, excimer laser902, ultrasonic machine tool 100 or the hot-forging process can also beused to machine the second trench in silicon wafer 202. In FIG. 15,dicing saw blade 502 is shown machining a second trench onto second side306 of silicon wafer 202. Coating 1102 is shown having been optionallyapplied in step 2002. FIGS. 10A and 10B show the resulting single anddouble bevel cuts respectively. In FIG. 10A a single cut has been madeon the silicon wafer 202 resulting in cutting angle Φ in a single bladeassembly. In FIG. 10B, a second trench has been machined into siliconwafer 202 (by any of the aforementioned trench machining processes) withthe same angle as the first trench. The result is a double bevel siliconbased surgical blade, with each cutting edge exhibiting a cutting angleof Φ, yielding a double bevel angle of 2Φ. FIG. 16 illustrates across-section image of a silicon wafer that has been machined trenchedon both sides, according to an embodiment of the invention.

Following machine trench step 2004, a decision must be made in decisionstep 2005, as to whether to etch the double machine trenched siliconwafer 202 in step 1018, or dice the double machine trenched siliconwafer 202 in step 1016. Dicing step 1016 can be performed by a dicingsaw blade, laser beam (e.g., an excimer laser, or laser waterjet 402).Dicing provides for the resultant strips to be etched (in step 1018) incustom fixtures in lieu of wafer boats (discussed in detail below).

FIGS. 17A and 17B illustrate an isotropic etching process performed on asilicon wafer with machined trenches on both sides, according to anembodiment of the present invention. In etching step 1018, the machinedsilicon wafer 202 is dismounted from tape 308. Silicon wafer 202 is thenplaced in a wafer boat and immersed in an isotropic acid bath 1400. Theetchant's 1402 temperature, concentration and agitation are controlledto maximize the uniformity of the etch process. The preferred isotropicetchant 1402 used is comprised of hydrofluoric acid, nitric acid, andacetic acid (HNA). Other combinations and concentrations can be used toachieve the same purpose. For example, water can be exchanged for theacetic acid. Spray etching, isotropic xenon diflouride gas etching, andelectrolytic etching, in lieu of immersion etching, can also be used toachieve the same results. Another example of a compound that can be usedin gas etching is sulfur hexafluoride, or other similar fluorinatedgases.

The etching process will uniformly etch both sides of silicon wafer 202and its respective trenches until the opposing trench profilesintersect. Silicon wafer 202 will be immediately removed from etchant1402 and rinsed once this occurs. The expected cutting edge radiusattained by this process ranges from 5 nm to 500 nm.

Isotropic chemical etching is a process that is used to remove siliconin a uniform manner. In the manufacturing process according to anembodiment of the present invention, the wafer surface profile that wasproduced with the machining described above is uniformly brought down tointersect with the profile on the opposing side of the wafer (if singlebevel blades are desired, the non-machined opposing silicon wafersurface will be intersected). Isotropic etching is used in order toachieve the desired blade sharpness while preserving the blade angle.Attempts to intersect the wafer profiles by machining alone fail becausethe desired edge geometry is too delicate to withstand the machiningmechanical and thermal forces. Each of the acidic components ofisotropic etchant (etchant) 1402 has a specific function in isotropicacid bath 1400. First, nitric acid oxidizes the exposed silicon, andsecondly, hydrofluoric acid removes the oxidized silicon. Acetic acidacts as a diluent during this process. Precise control of composition,temperature and agitation is necessary to achieve repeatable results.

In FIG. 17A silicon wafer 202, with no coating 1102, has been placed inisotropic etch bath 1400. Note that each surgical blade, first surgicalblade 1404, second surgical blade 1406, and third surgical blade 1408,are connected to each other. As etchant 1402 works on the silicon, onelayer after another of molecules is removed over time, decreasing thewidth of the silicon (i.e., the surgical blade) until the two angles,1410 and 1412 (of first surgical blade 1404), intersect at the pointwhere they are joined to the next surgical blade (second surgical blade1406). The result is that several surgical blades (1404, 1406 and 1408)are formed. Note that the same angles have been maintained throughoutthe isotropic etching process, except that less silicon material remainsbecause it has been dissolved by etchant 1402.

FIGS. 18A and 18B illustrate an isotropic etching process on a siliconwafer with machined trenches on both sides, and a coating layer on oneside, according to another embodiment of the present invention. In FIGS.18A and 18B, tape 308 and coating 1102 have been left on silicon wafer202 so that the etching process only acts upon second side 306 ofsilicon wafer 202. It is not necessary that the wafer be mounted on tapeduring the etching process; this is only a manufacturing option. Again,isotropic etch material 1402 works upon the exposed silicon wafer 202solely, removing silicon material (one layer after another), butmaintaining the same angle as was machined in step 2004 (because this issecond side 306). As a result, in FIG. 18B, silicon based surgicalblades 1504, 1506 and 1508 have the same angle as was machined in steps1008 and 2004, on first side 304, because of tape 308 and optionalcoating 1102, and on second side 306, because isotropic etchant 1402removes uniform layers of silicon molecules along the machined trenchsurface. First side 304 of silicon wafer 202 has not been etched at all,providing additional strength to the finished silicon based surgicalblade.

Another benefit of using optional step 2002, applying coating 1102 tofirst side 304 of silicon wafer 202, is that the cutting edge (the firstmachined trench side) is composed of coating 1102 (which is preferrablycomprised of a layer of silicon nitride) that possesses strongermaterial properties than the base silicon material. Therefore, theprocess of applying coating 1102 results in a cutting edge that isstronger and more durable. Coating 1102 also provides a wear-barrier tothe blade surface which can be desirable for blades that come in contactwith steel in electromechanical reciprocating blade devices. Table Iillustrates typical strength-indicating specifications of a siliconbased surgical blade manufactured without coating 1102 (silicon) andwith coating 1102 (silicon nitride).

TABLE 1 Property Silicon Silicon Nitride Young's Modulus (GPa) 160 323Yield Strength (GPa) 7 14

Young's Modulus (also known as the modulus of elasticity) is ameasurement of a material's inherent stiffness. The higher the modulus,the stiffer the material. Yield strength is the point at which amaterial, under load, will transition from elastic to plasticdeformation. In other words, it is the point at which the material willno longer flex, but will permanently warp or break. After etching (withor without coating 1102), the etched silicon wafer 202 is thoroughlyrinsed and cleaned to remove all residual etchant 1402 chemicals.

FIG. 19 illustrates a resultant cutting edge of a double bevel siliconsurgical blade with a coating on one side manufactured according to anembodiment of the present invention. The cutting edge 1602 typically hasa radius of 5 to 500 nanometers which is similar to that of a diamondsurgical blade, but manufactured at much less cost. After the etchingprocess of step 1018 has been performed, silicon based surgical bladescan be mounted according to step 1020, which is the same as mountingsteps 1002 and step 2003.

Following mounting step 1020, the silicon based surgical blades (siliconblades) can be singulated in step 1022, which means that each siliconblade is cut apart through use of a dicing saw blade, laser beam (e.g.,laser waterjet 402 or an excimer laser), or other suitable means toseparate the silicon blades from each other. As one skilled in the artcan appreciate, lasers with certain wavelengths within the range of 150nm to 11,000 nm can also be used. An example of a laser in thiswavelength range is an excimer laser. The uniqueness of the laserwaterjet (a YAG laser) is that it can scroll curvilinear, interruptedpatterns in the wafer. This provides the manufacturer the flexibility tomake virtually an unlimited number of non-cutting edge blade profiles.The laser waterjet uses a stream of water as a waveguide that allows thelaser to cut like a band saw. This cannot be achieved with the currentstate of the art dicing machines, which, as mentioned above, can onlydice in continuous, straight-line patterns.

In step 1024 the singulated surgical silicon blades are picked andplaced on blade handle assemblies, according to the particular desiresof the customers. Prior to actual “picking and placing” however, theetched silicon wafers 202 (being mounted on either tape and frame or ona tape/wafer frame) are radiated by ultraviolet (UV) light in the wafermounting machine to reduce tape 308 tackiness. Silicon wafers 202, stillon the “reduced tackiness” tape and frame, or tape/wafer frame, are thenloaded into a commercially available die-attach assembly system. Recallfrom above it was discussed that the order of certain steps can beinterchanged according to various manufacturing environments. One suchexample are the steps of singulation and radiation by UV light: thesesteps can be interchanged if necessary.

The die-attach assembly system will remove the individual etched siliconsurgical blades from the “reduced tackiness” tape and wafer ortape/wafer frame, and will attach the silicon surgical blades to theirrespective holders within the desired tolerance. An epoxy or adhesivewill be used to mount the two components. Other assembly methods can beused to attach the silicon surgical blade to its respective substrate,including heat staking, ultrasonic staking, ultrasonic welding, laserwelding or eutectic bonding. Lastly in step 1026, the fully assembledsilicon surgical blades with handles, are packaged to ensure sterilityand safety, and transported for use according to the design of thesilicon surgical blade.

Another assembly method that can be used to mount the surgical blade toits holder involves another use of slots. Slots, as discussed above, canbe created by the laser water-jet or excimer laser, and were used toprovide an opening for the dicing saw blade to engage the silicon wafer202 when machining trenches. An additional use of slots can be toprovide a receptacle in the blade for one or more posts in a holder.FIG. 24 illustrates such an arrangement. In FIG. 24, finished surgicalblade 2402 has had two slots 2404 a, 2404 b created in its holderinterface region 2406. These interface with posts 2408 a, 2408 b ofblade holder 2410. The slots can be cut into the silicon wafer 202 atany point in the manufacturing process, but preferably can be done priorto singulation of the surgical blades. Prior to being interfaced, anadhesive can be applied to the appropriate areas, assuring a tight hold.Then, cover 2412 can be glued as shown, to provide a finished appearanceto the final product. The purpose for implementing the post-slotassembly is that it provides additional resistance to any pulling forcethat blade 2402 might encounter during a cutting procedure.

Having described the manufacturing process for a double bevelsilicon-based surgical blade, attention is turned to FIG. 2, whichillustrates a flow diagram of a method for manufacturing a single bevelsurgical blade from silicon according to a second embodiment of thepresent invention. Steps 1002, 1004, 1006, 1008 of FIG. 1 are the samefor the method illustrated in FIG. 2, and therefore will not berepeated. However, the method for manufacturing a single bevel surgicalblade differs in the next step, step 1010, from the method formanufacturing a double bevel blade, and therefore, will be discussed indetail.

Following step 1008 decision step 1010 determines whether the machinedsilicon wafer 202 will be dismounted from silicon wafer mountingassembly 204. If the single trench silicon wafers 202 were to bedismounted (in step 1012), then a further option is to dice the singletrench wafers in step 1016. In optional dismounting step 1012, thesilicon wafer 202 is dismounted from tape 308 utilizing the samestandard mounting machine.

If silicon wafer 202 was dismounted in step 1012, then optionally thesilicon wafer 202 can be diced (i.e., silicon wafer 202 cut apart intostrips) in step 1016. Dicing step 1016 can be performed by a dicingblade, excimer laser 902, or laser waterjet 402. Dicing provides for theresultant strips to be etched (in step 1018) in custom fixtures in lieuof wafer boats (discussed in detail below). Following either the dicingstep of 1016, the dismounting step of 1012, or the machine trench stepof 1008, the next step in the method for manufacturing a single bevelsilicon based surgical blade is step 1018. Step 1018 is the etchingstep, which has already been discussed in detail above. Thereafter,steps 1020, 1022, 1024 and 1026 follow, all of which have been describedin detail above in reference to the manufacture of a double bevelsilicon based surgical blade, and therefore do not need to be discussedagain.

FIG. 3 illustrates a flow diagram of an alternative method formanufacturing a single bevel surgical blade from silicon according to athird embodiment of the present invention. The method illustrated inFIG. 3 is identical to that illustrated in FIG. 2, through steps 1002,1004, 1006, 1008. After step 1008 in FIG. 3, however, there is coatingstep 2002. The coating step 2002 was described above in reference toFIG. 1, and need not be discussed in detail again. The result of thecoating step is the same as was described previously: the machined sideof silicon wafer 202 has a layer 1102 over it.

Following the coating step 2002, the silicon wafer 202 is dismounted andremounted in step 2003. This step is also identical as was previouslydiscussed in reference to FIG. 1 (step 2003). The result is that thecoated side of silicon wafer 202 is face down on the mounting assembly204. Thereafter, steps 1018, 1020, 1022, 1024 and 1026 take place, allof which have been described in detail above. The net result is a singlebevel surgical blade, with the first side 304 (machined side) providedwith a layer of coating 1102 to improve the strength and durability ofthe surgical blade. FIGS. 23A and 23B illustrate and describe the singlebevel coated surgical blade in greater detail.

FIGS. 23A and 23B illustrate an isotropic etching process on a siliconwafer with a machined trench on one side, and a coating layer on anopposite side according to a further embodiment of the presentinvention. As described above, silicon wafer 202 has coating 1102applied to first side 304 which is then mounted onto tape 308, thuscoming in close contact with it, as shown in FIG. 23A. Silicon wafer 202is then placed in bath 1400, which contains etchant 1402, as discussedin detail above. Etchant 1402 begins to etch the second side 306 (“topside”) of silicon wafer 202, removing one layer after another of siliconmolecules. After a period of time, silicon wafer 202 has its thicknessreduced by etchant 1402 until second side 306 comes in contact withfirst side 304 and coating 1102. The result is a silicon nitride coatedsingle bevel silicon based surgical blade. All of the aforementionedadvantages of having a silicon nitride (or coated) blade edge applyequally to this type of blade as shown and discussed in reference toFIGS. 18A, 18B and 19.

FIGS. 20A-20G illustrate various examples of silicon based surgicalblades that can be manufactured in accordance with the method of thepresent invention. Various blade designs can be manufactured utilizingthis process. Blades with single bevels, symmetric and asymmetric doublebevels, and curvilinear cutting edges can be produced. For singlebevels, the machining is only performed on one side of the wafer.Various blade profiles can be made, such as single edge chisel (FIG.20A), three edge chisel (FIG. 20B), slit, two edges sharp (FIG. 20C),slit, four edges sharp (FIG. 20D), stab, one edge sharp (FIG. 20E),keratome, one edge sharp (FIG. 20F) and crescent, curvilinear sharp edge(FIG. 20G). The profile angles, widths, lengths, thicknesses, and bevelangles can be varied with this process. This process can be combinedwith traditional photolithography to produce more variations andfeatures.

FIGS. 21A and 21B illustrate a side view of a silicon surgical blademanufactured in accordance with an embodiment of the invention, and astainless steel surgical blade, at 5,000× magnification, respectively.Note the difference between FIGS. 21A and 21B. FIG. 21A is much smootherand more uniform. FIGS. 22A and 22B illustrate top views of the bladeedge of a silicon surgical blade manufactured in accordance with anembodiment of the invention and a stainless steel blade, at 110,000×magnification, respectively. Again, the difference between FIG. 22A andFIG. 22B is that the former, the result of the method according to anembodiment of the invention, is much smoother and more uniform than thestainless steel blade of FIG. 22B.

FIGS. 25A and 25B illustrate profile perspectives of a blade edge madeof a crystalline material, and a blade edge made of a crystallinematerial that includes a layer conversion process in accordance with anembodiment of the invention. In another embodiment of the invention, itis possible to chemically convert the surface of the substrate materialto a new material 2504 after etching the silicon wafer. This step canalso be known as a “thermal oxidation, nitride conversion” or “siliconcarbide conversion of the silicon surface” step. Other compounds can becreated depending on which elements are allowed to interact with thesubstrate/blade material. The benefit of converting the surface of theblade to a compound of the substrate material is that the newmaterial/surface can be selected such that a harder cutting edge iscreated. But unlike a coating, the cutting edge of the blade maintainsthe geometry and sharpness of the post etch step. Note that in FIGS. 25Aand 25B, the depth of the silicon blade has not changed because of theconversion process; “D1” (the depth of the silicon-only blade) is equalto “D2” (the depth of the silicon blade with a conversion layer 2504).

Referring to FIG. 1, after step 1018 a decision is made to convert thesurface (decision step 1019). If a conversion layer is to be added(“Yes” path from decision step 1019), a conversion layer is added instep 1021. The method then proceeds to step 1020. If no conversion layeris to be added (“No” path from decision step 1019), the method proceedsto step 1020. The conversion process requires diffusion or hightemperature furnaces. The substrate is heated under vacuum or in aninert environment to a temperature in excess of 500° C. Selected gassesare metered into the furnace in controlled concentrations and as aresult of the high temperature they diffuse into the silicon. As theydiffuse into the silicon they react with the silicon to form a newcompound. Since the new material is created by diffusion and chemicalreaction with the substrate rather then applying a coating, the originalgeometry (sharpness) of the silicon blade is preserved. An additionalbenefit of the conversion process is that the optical index ofrefraction of the converted layer is different than that of thesubstrate so the blade appears to be colored. The color depends both onthe composition of the converted material and it's thickness.

A single crystal substrate material that has been converted at thesurface also exhibits superior fracture and wear resistance than a nonconverted blade. By changing the surface to a harder material thetendency of the substrate to form crack initiation sites and cleavealong crystalline planes is reduced.

A further example of a manufacturing step that can be performed withsome interchangeability is the matte-finish step. Often, especially whenmanufactured in the preferred embodiment of surgical blades, the siliconsurface of the blade will be highly reflective. This can be distractingto the surgeon if the blade is being used under a microscope with asource of illumination. Therefore, the surface of the blade can beprovided with a matte finish that diffuses incident light (from ahigh-intensity lamp used during surgical procedure, for example), makingit appear dull, as opposed to shiny. The matte finish is created byradiating the blade surface with a suitable laser, to ablate regions inthe blade surface according to specific patterns and densities. Theablated regions are made in the shape of a circle because that isgenerally the shape of the emitted laser beam, though that need not bethe case. The dimension of the circular ablated regions ranges from25-50 microns in diameter, and again is dependent upon the manufacturerand type of laser used. The depth of the circular ablated regions rangesfrom 10-25 microns.

The “density” of circular ablated regions refers to the total percentagesurface area covered by the circular ablated regions. An “ablated regiondensity” of about 5% dulls the blade noticeably, from its normallysmooth, mirror-like appearance. However, co-locating all the ablatedregions does not affect the mirror-like effect of the balance of theblade. Therefore the circular ablated regions are applied throughput thesurface area of the blade, but in a random fashion. In practice, agraphic file can be generated that randomly locates the depressions, butachieves the desired effect of a specific ablated region density andrandomness to the pattern. This graphic file can be created manually, orautomatically by a program in a computer. An additional feature that canbe implemented is the inscription of serial numbers, manufacturer logos,or the surgeon's or hospital's name on the blade itself.

Typically, a gantry laser can be used to create the matte finish on theblades, or a galvo-head laser machine. The former is slow, but extremelyaccurate, and the latter is fast, but not as accurate as the gantry.Since the overall accuracy is not vital, and speed of manufacturingdirectly affects cost, the galvo-head laser machine is the preferredtool. It is capable of moving thousands of millimeters per second,providing an overall ablated region etch time of about five seconds fora typical surgical blade.

The present invention has been described with reference to certainexemplary embodiments thereof. However, it will be readily apparent tothose skilled in the art that it is possible to embody the invention inspecific forms other than those of the exemplary embodiments describedabove. This may be done without departing from the spirit and scope ofthe invention. The exemplary embodiment is merely illustrative andshould not be considered restrictive in any way. The scope of theinvention is defined by the appended claims and their equivalents,rather than by the preceding description.

1. A method for manufacturing a cutting device from a crystallinematerial, the method comprising: making at least one blade profile in awafer of a first material; coating at least a first side of the wafercomprising the at least one blade profile; mounting the wafer on thefirst side before the etching; and isotropically etching the wafer toform at least one blade comprising the at least one blade profile. 2.The method according to claim 1, wherein the making step comprises:machining at least one blade profile in the wafer with at least one of adicing blade and a laser beam.
 3. The method according to claim 2,wherein the laser beam is produced by at least one of an excimer laserand a laser waterjet.
 4. The method according to claim 2, wherein thelaser beam comprises a wavelength in the range of about 150 nanometersto 11,000 nanometers.
 5. The method according to claim 1, wherein themaking step comprises: machining at least one blade profile in the waferwith an ultrasonic machine.
 6. The method according to claim 1, whereinthe making step comprises: machining at least one blade profile in thewafer with a hot forging process.
 7. The method according to claim 1,wherein the etching comprises: placing the wafer comprising the at leastone blade profile on a wafer boat; immersing the wafer boat and thewafer comprising the at least one blade profile in an isotropic acidbath; etching the wafer such that the first material of the wafer isremoved on any exposed surface, whereby a sharp blade edge is etched inthe shape of the at least one blade profile.
 8. The method according toclaim 7, wherein the isotropic acid bath comprises: at least one of ahydrofluoric acid and nitric acid.
 9. The method according to claim 8,wherein the isotropic acid bath further comprises: at least one ofacetic acid and water.
 10. The method according to claim 1, wherein theetching comprises: placing the wafer comprising the at least one bladeprofile in a wafer boat; spraying a spray etchant at the wafer boat andthe wafer comprising the at least one blade profile; etching the waferwith the spray etchant such that the first material of the wafer isremoved on any exposed surface, whereby a sharp blade edge is etched inthe shape of the at least one blade profile.
 11. The method according toclaim 1, wherein the etching comprises: placing the wafer comprising theat least one blade profile on a wafer boat; immersing the wafer boat andthe wafer comprising the at least one blade profile in an isotropicxenon difluoride, sulfur hexafluoride or similar fluorinated gasenvironment; etching the wafer with the isotropic xenon difluoride,sulfur hexafluoride or similar fluorinated gas such that the firstmaterial of the wafer is removed on any exposed surface, whereby a sharpblade edge is etched in the shape of the at least one blade profile. 12.The method according to claim 1, wherein the etching comprises: placingthe wafer comprising the at least one blade profile in a wafer boat;immersing the wafer boat and the wafer comprising the at least one bladeprofile in an electrolytic bath; etching the wafer with the electrolyticbath such that the first material of the wafer is removed on any exposedsurface, whereby a sharp blade edge is etched in the shape of the atleast one blade profile.
 13. The method according to claim 1, furthercomprising singulating the at least one blade.
 14. The method accordingto claim 13, wherein the singulating comprises: dicing the machinedwafer with at least one of a dicing blade and a laser beam.
 15. Themethod according to claim 14, wherein the laser beam is produced by atleast one of an excimer laser and a laser waterjet.
 16. The methodaccording to claim 1, further comprising: dicing the machined waferafter making the at least one blade profile in the form of single bevelblade and prior to the step of etching.
 17. The method according toclaim 16, wherein the dicing comprises: dicing the machined wafer withat least one of a dicing blade and a laser beam.
 18. The methodaccording to claim 17, wherein the laser beam is produced by at leastone of an excimer laser and a laser waterjet.
 19. The method accordingto claim 17, wherein the laser beam comprises a wavelength in the rangeof about 150 nanometers to 11,000 nanometers.
 20. The method accordingto claim 1, wherein the making of the at least one blade profilecomprises: making a first blade profile in the wafer on a first side ofthe wafer; and making a second blade profile in the wafer on a secondside of the wafer.
 21. The method according to claim 14, wherein thelaser beam comprises a wavelength in the range of about 150 nanometersto 11,000 nanometers.
 22. The method according to claim 2, wherein thelaser beam comprises a wavelength of about 1064 nanometers or about 355nanometers.
 23. The method according to claim 3, wherein the laser beamproduced by the excimer laser comprises a wavelength of about 157nanometers to 248 nanometers.
 24. The method according to claim 2,wherein the laser beam is produced by a YaG laser.
 25. The methodaccording to claim 24, wherein the laser beam comprises a wavelength ofabout 1064 nanometers or about 355 nanometers.
 26. The method accordingto claim 14, wherein the laser beam comprises a wavelength of about 1064nanometers or about 355 nanometers.
 27. The method according to claim15, wherein the laser beam produced by the excimer laser comprises awavelength of about 157 nanometers to 248 nanometers.
 28. The methodaccording to claim 14, wherein the laser beam is produced by a YaGlaser.
 29. The method according to claim 28, wherein the laser beamcomprises a wavelength of about 1064 nanometers or about 355 nanometers.30. The method according to claim 17, wherein the laser beam comprises awavelength of about 1064 nanometers or about 355 nanometers.
 31. Themethod according to claim 18, wherein the laser beam produced by theexcimer laser comprises a wavelength of about 157 nanometers to 248nanometers.
 32. The method according to claim 17, wherein the laser beamis produced by a YaG laser.
 33. The method according to claim 32,wherein the laser beam comprises a wavelength of about 1064 nanometersor about 355 nanometers.
 34. The method according to claim 1, whereinthe making of the at least one blade profile in the wafer comprisesmaking the at lest one blade profile to a depth of about 50 to 90percent of a thickness of the wafer.
 35. The method according to claim20 wherein the making of at least one of the first blade profile and thesecond blade profile comprises making the at lest one of the first bladeprofile and the second blade profile to a depth of about 25 to 49percent of a thickness of the wafer.
 36. The method according to claim1, wherein the coating comprises applying a layer of material comprisingat least one of silicon nitride, titanium nitride, aluminum titaniumnitride, silicon dioxide, silicon carbide, titanium carbide, boronnitride, and diamond-like-crystals.
 37. The method according to claim20, further comprising dicing the wafer comprising the first bladeprofile and the second blade profile into separated double beveled bladeprofiles before the etching.
 38. The method according to claim 37,wherein the dicing comprises dicing the wafer with at least one of adicing blade and a laser beam.
 39. The method according to claim 38,wherein the laser beam is produced by at least one of an excimer laserand a laser waterjet.
 40. The method according to claim 38, wherein thelaser beam comprises a wavelength in the range of about 150 nanometersto 11,000 nanometers.
 41. The method according to claim 38, wherein thelaser beam comprises a wavelength of about 1064 nanometers or about 355nanometers.
 42. The method according to claim 39, wherein the laser beamproduced by the excimer laser comprises a wavelength of about 157nanometers to 248 nanometers.
 43. The method according to claim 38,wherein the laser beam is produced by a YaG laser.
 44. The methodaccording to claim 43, wherein the laser beam comprises a wavelength ofabout 1064 nanometers or about 355 nanometers.
 45. The method accordingto claim 1, wherein the first material of the wafer comprises at leastone of a crystalline material and a polycrystalline material.
 46. Themethod according to claim 1, wherein the first material of the wafercomprises at least one of a silicon, silicon nitride an galliumarsenide.
 47. The method according to claim 45, wherein orientation ofthe silicon wafer comprises at least one of <100>, <110>, <111>.
 48. Themethod according to claim 1, further comprising converting at least aportion of the first material of the wafer into a second material. 49.The method according to claim 48, wherein the converting is performedafter the etching.
 50. The method according to claim 48, wherein theconverting comprises at least one of thermal oxidation, silicon nitrideconversion and silicon carbide conversion.
 51. The method according toclaim 48, wherein a thickness of the at least one blade comprising thefirst material is approximately equal to a thickness of the bladecomprising the first material and the second material.
 52. A method formanufacturing a cutting device, the method comprising: cutting at leastone of a through hole fiducial and a slot in a wafer comprising a firstmaterial; making at least one blade profile in the wafer using the atleast one of the through hole fiducial and the slot as a guide; andetching the wafer to form at least one blade comprising the at least oneblade profile.
 53. The method according to claim 52, further comprisingsingulating the at least one blade.
 54. The method according to claim52, wherein the cutting comprises cutting the at least one of a throughhole fiducial and a slot using a mechanical machining device.
 55. Themethod according to claim 54, wherein the mechanical machining devicecomprises at least one of a drilling tool, an ultrasonic machining tooland a mechanical grinding device.
 56. The method according to claim 52,wherein the making step comprises machining the at least one bladeprofile in the wafer with a dicing blade.
 57. The method according toclaim 52, wherein the etching of the wafer comprises isotropicallyetching the wafer to form the at least one blade comprising the at leastone blade profile.
 58. The method according to claim 52, wherein atleast one of the cutting and the making comprises removing at least aportion of the first material of the wafer by a laser beam.
 59. Themethod according to claim 58, wherein the laser beam is produced by atleast one of an excimer laser and a laser waterjet.
 60. The methodaccording to claim 58, wherein the laser beam comprises a wavelength inthe range of about 150 nanometers to 11,000 nanometers.
 61. The methodaccording to claim 58, wherein the laser beam comprises a wavelength ofabout 1064 nanometers or about 355 nanometers.
 62. The method accordingto claim 59, wherein the laser beam produced by the excimer lasercomprises a wavelength of about 157 nanometers to 248 nanometers. 63.The method according to claim 58, wherein the laser beam is produced bya YaG laser.
 64. The method according to claim 63, wherein the laserbeam comprises a wavelength of about 1064 nanometers or about 355nanometers.
 65. The method according to claim 53, wherein thesingulating comprises dicing the machined wafer with at least one of adicing blade and a laser beam.
 66. The method according to claim 65,wherein the laser beam is produced by at least one of an excimer laserand a laser waterjet.
 67. The method according to claim 65, wherein thelaser beam comprises a wavelength in the range of about 150 nanometersto 11,000 nanometers.
 68. The method according to claim 65, wherein thelaser beam comprises a wavelength of about 1064 nanometers or about 355nanometers.
 69. The method according to claim 66, wherein the laser beamproduced by the excimer laser comprises a wavelength of about 157nanometers to 248 nanometers.
 70. The method according to claim 65,wherein the laser beam is produced by a YaG laser.
 71. The methodaccording to claim 70, wherein the laser beam comprises a wavelength ofabout 1064 nanometers or about 355 nanometers.
 72. The method accordingto claim 52, further comprising coating at least a first side of thewafer comprising the at least one blade profile.
 73. The methodaccording to claim 72, wherein the coating comprises applying a layer ofmaterial comprising at least one of silicon nitride, titanium nitride,aluminum titanium nitride, silicon dioxide, silicon carbide, titaniumcarbide, boron nitride, and diamond-like-crystals.
 74. The methodaccording to claim 52, wherein the first material of the wafer comprisesat least one of a crystalline material and a polycrystalline material.75. The method according to claim 52, wherein the first material of thewafer comprises at least one of a silicon, silicon nitride an galliumarsenide.
 76. The method according to claim 75, wherein orientation ofthe silicon wafer comprises at least one of <100>, <110>, <111>.
 77. Themethod according to claim 52, further comprising converting at least aportion of the first material of the wafer into a second material. 78.The method according to claim 77, wherein the converting is performedafter the etching.
 79. The method according to claim 78, wherein theconverting comprises at least one of thermal oxidation, nitrideconversion and silicon carbide conversion.
 80. The method according toclaim 78, wherein a thickness of the at least one blade comprising thefirst material is approximately equal to a thickness of the bladecomprising the first material and the second material.
 81. The methodaccording to claim 52, wherein the making of the at least one bladeprofile in the wafer comprises making the at lest one blade profile to adepth of about 50 to 90 percent of a thickness of the wafer.
 82. Themethod according to claim 53, further comprising: mounting the wafer ona mounting assembly; and radiating the singulated blade withultra-violet light, to separate the singulated blade from the mountingassembly.
 83. The method according to claim 1, wherein the etchingcomprises: immersing the at least one blade profile in an isotropic acidbath; etching the wafer such that the first material of the wafer isremoved on any exposed surface, whereby a sharp blade edge is etched inthe shape of the at least one blade profile.
 84. The method according toclaim 83, wherein the isotropic acid bath comprises: at least one of ahydrofluoric acid and nitric acid.
 85. The method according to claim 84,wherein the isotropic acid bath further comprises: at least one ofacetic acid and water.
 86. The method according to claim 1, wherein theetching comprises: spraying a spray etchant at the wafer comprising theat least one blade profile; etching the wafer with the spray etchantsuch that the first material of the wafer is removed on any exposedsurface, whereby a sharp blade edge is etched in the shape of the atleast one blade profile.
 87. The method according to claim 1, whereinthe etching comprises: immersing the wafer comprising the at least oneblade profile in an isotropic xenon difluoride, sulfur hexafluoride orsimilar fluorinated gas environment; etching the wafer with theisotropic xenon difluoride, sulfur hexafluoride or similar fluorinatedgas such that the first material of the wafer is removed on any exposedsurface, whereby a sharp blade edge is etched in the shape of the atleast one blade profile.
 88. The method according to claim 1, whereinthe etching comprises: placing the wafer of crystalline material withcomprising the at least one blade profile in a wafer boat; immersing thewafer comprising the at least one blade profile in an electrolytic bath;etching the wafer with the electrolytic bath such that the firstmaterial of the wafer is removed on any exposed surface, whereby a sharpsurgical blade edge is etched in the shape of the at least one bladeprofile.